Motion detector circuit – working and application

How to make a Motion detector circuit

Motion detector is also known as motion sensor. It is one of the most popular devices commonly used in tech based security providing products. A motion detector sensor senses moving subjects, mostly people and provide the correct results as per the motion detector circuit design.

The days are gone when motion sensor circuit were only used in security alarm systems. In this age of automation, motion sensor are used in end numbers of applications such as energy efficiency system, home automation system and there are plenty other examples.

Working of Motion detector

On the basis of the requirement, a motion sensor can be built by using different kinds of sensors such as microwave sensor (detection of person movement can be achieved by measuring changes in frequency), passive infrared sensor (detection of person movement can be achieved by person’s body heat), ultrasonic sensor (detection of person movement can be achieved by producing acoustic signals), etc. In order to produce accurate results in motion detection, most of the motion sensors uses different types of sensors at one time.

To make a simple yet reliable motion detector circuit, you can use IR detector for sending the IR beams along with a photo transistor for receiving the IR beams. Throughout the circuit, if IR sensor find any interference or disturbance while sending or receiving IR beams, it will show that there is an intrusion then creates the alert via the alarm. This sort of motion detector circuit is very easy to construct and implement. The best part is that their cost of circuit is very low as compared with other types of normal motion detectors.

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Components used in constructing motion detector circuit

IR sensor

The chief reason of using IR sensor is to produce such IR beams whose wavelength is shorter than microwaves but longer than visible rays. Generally, IR sensors are based on three different laws- Wien’s displacement law, Stephan Boltzmann law and Planks radiation law. In IR sensors, source and transmission of IR beams are the two most important aspects. Apart from these two things, there are few other sources such as silicon carbide in IR sensors, tungsten lamps and black body radiators. Few common transmission medium used in IR sensors are optical fiber, air etc.

Photo transistor

It is another most important component used in constructing motion detector circuit. The main concept of using photo transistor in motion detectors is to identify and detects IR beams or radiations and convert them into voltage or current.

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Applications of motion detector circuit

• Motion detectors can be used in traffic light control systems.
• Usually, motion sensors are used as an intruder alarm in shopping complexes, banks, home, offices, government organizations etc.
• Motion sensors can also be used in automated control systems, home automation systems and energy efficient systems.